Статті в журналах: "Time Division Duplexing, TDD"

1

Iancu, Daniel, John Glossner, Gary Nacer, Stuart Stanley, Vitaly Kolashnikov, and Joe Hoane. "Software defined radio platform with wideband tunable front end." International Journal of Engineering & Technology 4, no. 1 (January 11, 2015): 97. http://dx.doi.org/10.14419/ijet.v4i1.4160.

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The paper presents a Software Defined Radio (SDR) development platform with wideband tunable RF (Radio Frequency) front end. The platform is based on the SB3500 Multicore Multithreaded Vector Processor and it is intended to be used for a wide variety of communication protocols as: Time Division Duplexing/Frequency Division Duplexing Long Term Evolution (TDD/FDD LTE), Global Positioning System (GPS), Global System for Mobile/General Packet Radio Service (GSM/GPRS), Wireless Local Area Network (WLAN), Legacy Worldwide Interoperability for Microwave Access (WiMAX). As an example, we describe briefly the implementation of the LTE TDD/FDD communication protocol. As far as we know, this is the only LTE category 1 communication protocol entirely developed and executed in software (SW), without any hardware (HW) accelerators.

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2

Imzhagi, Riskafian Medika, Hasanah Putri, and Hendrik Dwi Priyanto. "Comparative Analysis of TDD Frame Structure Technology LTE-Advanced (A Case Study in Cibitung Area Indonesia)." Journal of Hunan University Natural Sciences 49, no. 1 (January 28, 2022): 141–48. http://dx.doi.org/10.55463/issn.1674-2974.49.1.18.

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Based on the results of the drive-test, it showed that 72.22% of the Gramapuri Tamansari Cibitung area had downlink throughput quality below the standard of Key Performance Indicator (KPI) parameter, which was less than 8 Mbps. In addition, based on the Operation and Support System (OSS) data, in this area, the value of Physical Resource Block (PRB) utilization reached 83.93%; thus, an additional capacity from the downlink was needed. This study aims to compare Time Division Duplexing (TDD) frame structure and Inter-Band Carrier Aggregation FDD-TDD method in the Cibitung area, with band 3 FDD 1800 MHz and band 40 TDD 2300 MHz by simulation using Atoll 3.3 software. The parameters measured are downlink throughput, uplink throughput, RSRP, SINR, and connected user. The simulation results showed improving downlink throughput by 63%, uplink throughput by 65%, and connected users by 4%.

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3

Dikmen, Osman, and Selman Kulaç. "Determination of Effective Mode Selection for Ensuring Spectrum Efficiency with Massive MIMO in IoT Systems." Sensors 19, no. 3 (February 9, 2019): 706. http://dx.doi.org/10.3390/s19030706.

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Wireless Sensor Networks (WSNs) based on Internet of Things (IoT) applications are increasing day by day. These applications include healthcare, infrastructure monitoring, smart homes, wearable devices and smart cars. However, considering the fact that many different application areas will emerge in next generation wireless communication systems, efficient use of frequency spectrum is important. Because the whole frequency spectrum is now very crowded, it is important to ensure maximum spectrum efficiency for effective WSNs based on IoT. This study sought to determine which mode more effectively achieves spectrum efficiency for the performance of effective IoT systems under given conditions with respect to the length of the pilot sequence, Time Division Duplexing (TDD) or Frequency Division Duplexing (FDD). The results were obtained by Monte Carlo simulations. To the best of our knowledge, a study of effective mode selection analysis for spectrum efficiency in IoT based systems has not been available in the literature yet. The results of this study are useful for determining the appropriate design conditions for WSNs based on IoT.

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4

Fan, Wei, Pekka Kyösti, Jesper Ø. Nielsen, Lassi Hentilä, and Gert F. Pedersen. "Emulating Realistic Bidirectional Spatial Channels for MIMO OTA Testing." International Journal of Antennas and Propagation 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/289843.

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This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on modeling bidirectional spatial channel models in multiprobe anechoic chamber (MPAC) setups. In the literature, work on this topic has been mainly focused on how to emulate downlink channel models, whereas uplink channel is often modeled as free space line-of-sight channel without fading. Modeling realistic bidirectional (i.e., both uplink and downlink) propagation environments is essential to evaluate any bidirectional communication systems. There have been works stressing the importance of emulating full bidirectional channel and proposing possible directions to implement uplink channels in the literature. Nevertheless, there is no currently published work reporting an experimental validation of such concepts. In this paper, a general framework to emulate bidirectional channels for time division duplexing (TDD) and frequency division duplexing (FDD) communication systems is proposed. The proposed technique works for MPAC setups with arbitrary uplink and downlink probe configurations, that is, possibly different probe configurations (e.g., number of probes or their configurations) in the uplink and downlink. The simulation results are further supported by measurements in a practical MPAC setup. The proposed algorithm is shown to be a valid method to emulate bidirectional spatial channel models.

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5

Franci, Daniele, Stefano Coltellacci, Enrico Grillo, Settimio Pavoncello, Tommaso Aureli, Rossana Cintoli, and Marco Donald Migliore. "An Experimental Investigation on the Impact of Duplexing and Beamforming Techniques in Field Measurements of 5G Signals." Electronics 9, no. 2 (January 29, 2020): 223. http://dx.doi.org/10.3390/electronics9020223.

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The fifth generation mobile network introduces dramatic improvements with respect to the previous technologies. Features such as variable numerology, bandwidth parts, massive Multiple Input Multiple Output (MIMO) and Time Division Duplex (TDD) will extend the capabilities of the 5G wireless systems and, at the same time, will influence the measurement techniques used to assess the compliance with general public electromagnetic field exposure limits. In this study, a heterogeneous set of 5G signals is investigated with the aim of establishing an effective measurement technique suitable for the new technology. Following an experimental approach based on both modulation and zero span analysis, some important characteristics of the 5G system are highlighted and extensively discussed, and experimental procedures for estimating factors associated to TDD (F T D C factor) and beam sweeping (R factor), to be used in the extrapolation formulas, are presented. The results of this study represent a starting point for future investigations on effective methods to estimate both the instant maximum power and the total power transmitted during a 5G radio frame.

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6

Lee, Jaewon, Minjoong Rim, and Chung G. Kang. "Decentralized Slot-Ordered Cross Link Interference Control Scheme for Dynamic Time Division Duplexing (TDD) in 5G Cellular System." IEEE Access 9 (2021): 63567–79. http://dx.doi.org/10.1109/access.2021.3074176.

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7

Quang, Khanh Nguyen, Van Duc Nguyen, and Hyunseung Choo. "Dynamic Subchannel Assignment-Based Cross-Layer MAC and Network Protocol for Multihop Ad Hoc Networks." Journal of Computer Networks and Communications 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/962643.

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The paper presents a dynamic subchannel assignment algorithm based on orthogonal frequency division multiple access technology operating in the time division duplexing and a new cross-layer design based on a proposed routing protocol jointed with the MAC protocol. The proposed dynamic sub-channel assignment algorithm provides a new interference avoidance mechanism which solves several drawbacks of existing radio resource allocation techniques in wireless networks using OFDMA/TDD, such as the hidden node and exposed node problems, mobility, and cochannels interference in frequency (CCI). Besides, in wireless networks, when a route is established, the radio resource allocation problems may decrease the end to end performance proportionally with the length of each route. The contention at MAC layer may cause the routing protocol at network layer to respond by finding new routes and routing table updates. The proposed routing protocol is jointed with the MAC protocol based on dynamic sub-channel assignment to ensure that the quality of service in multihop ad hoc networks is significantly improved.

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8

Wang, Li, Xiaoyan Zhao, Cheng Wang, and Weidong Wang. "Resource Allocation Algorithm Based on Power Control and Dynamic Transmission Protocol Configuration for HAPS-IMT Integrated System." Electronics 11, no. 1 (December 23, 2021): 44. http://dx.doi.org/10.3390/electronics11010044.

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The high altitude platform station (HAPS) system is an essential component of the air-based network. It can shorten transmission delay and make a better user experience compared with satellite networks, and it can also be easily deployed and cover a larger area compared with international mobile telecommunications (IMT). In order to meet the needs of users with asymmetric and random data flow, the spectrum sharing and dynamic time division duplexing (TDD) mode are used in HAPS-IMT heterogeneous network. However, the cross-link interference brought by TDD mode will lead to the degradation of system performance. In this paper, a resource allocation algorithm based on power control and dynamic transmission protocol configuration is proposed. Firstly, a specific timeslot, “low power almost-bank subframe (LP-ABS)”, is introduced into the frame structure of the HAPS physical layer. The transmission protocol designing could mitigate inter-layer interference efficiently by power control in “LP-ABS”. Secondly, the utilization function is adopted for assessing the system performance, which gives attention to both diversified requirements on the quality of services (QoS) and the throughput of the HAPS-IMT system. Simulation results show that power control and resource allocation technologies proposed in this paper can effectively improve system performance and user satisfaction.

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9

Franci, Daniele, Stefano Coltellacci, Enrico Grillo, Settimio Pavoncello, Tommaso Aureli, Rossana Cintoli, and Marco Donald Migliore. "Experimental Procedure for Fifth Generation (5G) Electromagnetic Field (EMF) Measurement and Maximum Power Extrapolation for Human Exposure Assessment." Environments 7, no. 3 (March 17, 2020): 22. http://dx.doi.org/10.3390/environments7030022.

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The fifth generation (5G) technology has been conceived to cover multiple usage scenarios from enhanced mobile broadband to ultra-reliable low-latency communications (URLLC) to massive machine type communications. However, the implementation of this new technology is causing increasing concern over the possible impact on health and safety arising from exposure to electromagnetic field radiated by 5G systems, making imperative the development of accurate electromagnetic field (EMF) measurement techniques and protocols. Measurement techniques used to assess the compliance with EMF exposure limits are object to international regulation. The basic principle of the assessment is to measure the power received from a constant radio frequency source, typically a pilot signal, and to apply a proper extrapolation factor. This kind of approach is standardized for 2G, 3G, and 4G technologies, but is still under investigation for 5G technology. Indeed, the use of flexible numerologies and advanced Time Division Duplexing (TDD) and spatial multiplexing techniques, such as beam sweeping and Massive Multiple Input Multiple Output (MIMO), requires the definition of new procedures and protocols for EMF measurement of 5G signals. In this paper a procedure for an accurate estimation of the instant maximum power received from a 5G source is proposed. The extrapolation technique is based on the introduction of proper factors that take into account the effect of the TDD and of the sweep beam in the measured value of the 5G signal level. Preliminary experimental investigation, based on code domain measurement of appropriate broadcast channels, and carried out in a controlled environment are reported, confirming the effectiveness of the proposed approach.

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10

Beyene, Yihenew, Kalle Ruttik, and Riku Jäntti. "Angular Domain Data-Assisted Channel Estimation for Pilot Decontamination in Massive MIMO." Mobile Information Systems 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/2785948.

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Massive Multiple-Input-Multiple-Output (M-MIMO) system is a promising technology that offers to mobile networks substantial increase in throughput. In Time-Division Duplexing (TDD), the uplink training allows a Base Station (BS) to acquire Channel State Information (CSI) for both uplink reception and downlink transmission. This is essential for M-MIMO systems where downlink training pilots would consume large portion of the bandwidth. In densely populated areas, pilot symbols are reused among neighboring cells. Pilot contamination is the fundamental bottleneck on the performance of M-MIMO systems. Pilot contamination effect in antenna arrays can be mitigated by treating the channel estimation problem in angular domain where channel sparsity can be exploited. In this paper, we introduce a codebook that projects the channel into orthogonal beams and apply Minimum Mean-Squared Error (MMSE) criterion to estimate the channel. We also propose data-aided channel covariance matrix estimation algorithm for angular domain MMSE channel estimator by exploiting properties of linear antenna array. The algorithm is based on simple linear operations and no matrix inversion is involved. Numerical results show that the algorithm performs well in mitigating pilot contamination where the desired channel and other interfering channels span overlapping angle-of-arrivals.

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11

Liang, Ya‐Chuan, Kai‐Kai Liu, Xue‐Ying Wu, Qing Lou, Lai‐Zhi Sui, Lin Dong, Kai‐Jun Yuan, and Chong‐Xin Shan. "Lifetime‐Engineered Carbon Nanodots for Time Division Duplexing." Advanced Science 8, no. 6 (February 2021): 2003433. http://dx.doi.org/10.1002/advs.202003433.

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12

Mamane, Asmae, Mohammed Fattah, Mohammed El Ghazi, and Moulhime El Bekkali. "5G Enhanced Mobile Broadband (eMBB): Evaluation of Scheduling Algorithms Performances for Time-Division Duplex Mode." International Journal of Interactive Mobile Technologies (iJIM) 16, no. 01 (January 18, 2022): 120–31. http://dx.doi.org/10.3991/ijim.v16i01.25941.

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5G mobile communications introduce novel solutions to overcome the frequency spectrum’s shortage. It broadens the spectrum band to millimeter-waves, employs multiple numerologies to calculate subcarrier spacing, and supports various division duplex modes. Furthermore, the fifth generation of mobile networks intends to employ both, frequency division duplex, and time division duplex. This study focuses on Time Division Duplex (TDD) mode. Compared to the Frequency Division Duplex (FDD), the time duplex mode enhances flexibility and allows efficient frequency spectrum usage. However, the recent papers addressing resource scheduling issues for TDD duplex employ only the current classical schedulers, which were primarily designed for FDD mode, to accomplish radio resource allocation. In this paper, we compared the achievable throughput and data accumulated in the buffer of these schedulers to assess their suitability and compatibility with TDD specifications. The resulting performances show that an appropriate scheduler in line with TDD requirements should be implemented to exploit the available spectrum efficiently and reach the required throughput.

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13

Guimaraes, Francisco R. V., Gabor Fodor, Walter C. Freitas, and Yuri C. B. Silva. "Pricing-Based Distributed Beamforming for Dynamic Time Division Duplexing Systems." IEEE Transactions on Vehicular Technology 67, no. 4 (April 2018): 3145–57. http://dx.doi.org/10.1109/tvt.2017.2777477.

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14

Lucani, Daniel E., Muriel Medard, and Milica Stojanovic. "On Coding for Delay—Network Coding for Time-Division Duplexing." IEEE Transactions on Information Theory 58, no. 4 (April 2012): 2330–48. http://dx.doi.org/10.1109/tit.2011.2177562.

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15

Kim, Hyun Geon, and Ho-Shin Cho. "Interference Management Using Crossed-Slot in Dynamic Time Division Duplexing Systems." IEEE Access 7 (2019): 135377–85. http://dx.doi.org/10.1109/access.2019.2942199.

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16

Al-awadi, Aws Majeed, and Mohammed Jawad Al-dujaili. "Simulation of LTE-TDD in the HAPS channel." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 3 (June 1, 2020): 3152. http://dx.doi.org/10.11591/ijece.v10i3.pp3152-3157.

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LTE stands for Long Term Evolution. This technology enhances the data rate and capacity using a new radio interface and an optimized core network. This progress was done to satisfy standards defined for the fourth generation of cellular communications in ITU. LTE has two types of transmission: Frequency Division Duplex (FDD) and Time Division Duplex (TDD). Nowadays, LTE-TDD rapidly Grows and takes place of old fixed cellular communications, like WiMAX. Another upcoming technology in the communication industry is High Amplitude Platform Stations (HAPS). Studying the capability of HAPS as a base station for LTE-TDD is the main purpose of this paper. Simulations have done using HAPS channel and compared to Stanford University Interim (SUI) standard channels for different scenarios. Results were compared to achieve a conclusion on HAPS implementation for LTE-TDD based on BER and data throughput.

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17

Chen, Xiangyu, Gang Chuai, and Weidong Gao. "Multi-Agent Reinforcement Learning Based Fully Decentralized Dynamic Time Division Configuration for 5G and B5G Network." Sensors 22, no. 5 (February 23, 2022): 1746. http://dx.doi.org/10.3390/s22051746.

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Future network services must adapt to the highly dynamic uplink and downlink traffic. To fulfill this requirement, the 3rd Generation Partnership Project (3GPP) proposed dynamic time division duplex (D-TDD) technology in Long Term Evolution (LTE) Release 11. Afterward, the 3GPP RAN#86 meeting clarified that 5G NR needs to support dynamic adjustment of the duplex pattern (transmission direction) in the time domain. Although 5G NR provides a more flexible duplex pattern, how to configure an effective duplex pattern according to services traffic is still an open research area. In this research, we propose a distributed multi-agent deep reinforcement learning (MARL) based decentralized D-TDD configuration method. First, we model a D-TDD configuration problem as a dynamic programming problem. Given the buffer length of all UE, we model the D-TDD configuration policy as a conditional probability distribution. Our goal is to find a D-TDD configuration policy that maximizes the expected discount return of all UE’s sum rates. Second, in order to reduce signaling overhead, we design a fully decentralized solution with distributed MARL technology. Each agent in MARL makes decisions only based on local observations. We regard each base station (BS) as an agent, and each agent configures uplink and downlink time slot ratio according to length of intra-BS user (UE) queue buffer. Third, in order to solve the problem of overall system revenue caused by the lack of global information in MARL, we apply leniency control and binary LSTM (BLSTM) based auto-encoder. Leniency controller effectively controls Q-value estimation process in MARL according to Q-value and current network conditions, and auto-encoder makes up for the defect that leniency control cannot handle complex environments and high-dimensional data. Through the parallel distributed training, the global D-TDD policy is obtained. This method deploys the MARL algorithm on the Mobile Edge Computing (MEC) server of each BS and uses the storage and computing capabilities of the server for distributed training. The simulation results show that the proposed distributed MARL converges stably in various environments, and performs better than distributed deep reinforcement algorithm.

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18

Yu, Rao, Chen Wei, and Cao Zhigang. "Downlink/uplink identification of time-division duplexing-OFDMA systems for cognitive radios." China Communications 10, no. 6 (June 2013): 68–78. http://dx.doi.org/10.1109/cc.2013.6549260.

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19

Hu, Sanqing, and Yu-Dong Yao. "Adaptive time division duplexing network with network coding embedded two-way relay." IET Communications 8, no. 12 (August 14, 2014): 2153–61. http://dx.doi.org/10.1049/iet-com.2013.0847.

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20

Kim, Hyeon-seong, and Ho-Shin Cho. "Time-Slot Allocation in Dynamic Time Division Duplexing System using Non-Orthogonal Multiple Access." Journal of the Korea Academia-Industrial cooperation Society 22, no. 8 (August 31, 2021): 32–39. http://dx.doi.org/10.5762/kais.2021.22.8.32.

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21

Backfrieder, Christian, and Gerald Ostermayer. "Analysis of an Adaptive Switching Point for LTE TDD by Dynamic System-Level Simulations." International Journal of Electronics and Telecommunications 61, no. 2 (June 1, 2015): 171–78. http://dx.doi.org/10.1515/eletel-2015-0022.

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Abstract This paper introduces an LTE system level simulator and presents investigations of scenarios with differently balanced traffic emergence between uplink and downlink as well as inhomogeneous distribution of link direction asymmetry. In the TDD mode of LTE, duplexing is implemented via sharing the time domain between uplink and downlink users. This is done by different switching configurations, which offer varying capacity distributions between downlink and uplink, from a downlink-heavy configuration with 90 percent of the capacity in downlink direction to uplink heavy configurations with 60 percent uplink. We utilize the available capacity perfectly by adjusting the link configuration appropriately to traffic emergence. Performance gains when selecting a configuration appropriate to the arising traffic compared to usage of a static configuration with equally distributed capacity are investigated. In case of different configurations, additional interference can occur in neighbored cells due to distinct communication direction at the same time. We clarify the differences between these scenarios and quantify the gains and losses when the switching point between uplink and downlink is variable.

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22

Peng, Xidan, and Xiangyang Li. "Performance Analysis for Analog Network Coding with Imperfect CSI in FDD Two Way Channels." Journal of Systems Science and Information 3, no. 4 (August 25, 2015): 357–64. http://dx.doi.org/10.1515/jssi-2015-0357.

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AbstractA time-division duplex (TDD) two-way channel exploits reciprocity to estimate the forward channel gain from the reverse link. Many previous works explore outage probabilities in the TDD system, based on the reciprocity property. However, a frequency-division duplex (FDD) system has no reciprocity property. In this letter, we investigate the impact of CSI estimation error on the performance of non-orthogonal and orthogonal analog network coding protocols in an FDD two-way system, where channel gains are independent of each other. Considering imperfect CSI, the closed-form expressions of outage probabilities by two protocols are derived in the high signal-to-noise ratio (SNR) regime, respectively. It is shown that the derived outage probabilities match results of Monte Carlo simulations in different communication scenarios. It is interesting that ANC in the FDD two-way channel is proved to outperform that in the TDD channel by the computer simulation.

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23

Papadopoulos, H. C., and C. E. W. Sundberg. "Reduction of mixed cochannel interference in microcellular shared time-division duplexing (STDD) systems." IEEE Transactions on Vehicular Technology 47, no. 3 (1998): 842–55. http://dx.doi.org/10.1109/25.704839.

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24

Ramamoorthi, Yoghitha, and Abhinav Kumar. "Dynamic Time Division Duplexing for Downlink/Uplink Decoupled Millimeter Wave-Based Cellular Networks." IEEE Communications Letters 23, no. 8 (August 2019): 1441–45. http://dx.doi.org/10.1109/lcomm.2019.2920641.

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25

Kim, Jun Suk, Bum-Gon Choi, Sueng Jae Bae, Inshil Doh, and Min Young Chung. "Adaptive time division duplexing configuration mode selection mechanism for accommodating asymmetric traffic in time division long term evolution-advanced systems." Transactions on Emerging Telecommunications Technologies 24, no. 3 (March 27, 2013): 342–51. http://dx.doi.org/10.1002/ett.2630.

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26

Magesacher, Thomas, and Elmar Trojer. "Single-Kernel Fast Fourier Transform/IFFT Processing for Time-Division Duplexing-Discrete Multi-Tone." Advanced Science Letters 19, no. 8 (August 1, 2013): 2515–18. http://dx.doi.org/10.1166/asl.2013.4965.

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27

Meurer, M., P. W. Baier, T. Weber, Y. Lu, and A. Papathanassiou. "Joint transmission: advantageous downlink concept for CDMA mobile radio systems using time division duplexing." Electronics Letters 36, no. 10 (2000): 900. http://dx.doi.org/10.1049/el:20000671.

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28

Xia, Pengfei, Robert W. Heath, and Nuria Gonzalez-Prelcic. "Robust Analog Precoding Designs for Millimeter Wave MIMO Transceivers With Frequency and Time Division Duplexing." IEEE Transactions on Communications 64, no. 11 (November 2016): 4622–34. http://dx.doi.org/10.1109/tcomm.2016.2604312.

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29

Wai-Choong Wong, C. E. W. Sundberg, and N. Seshadri. "Shared time division duplexing: an approach to low-delay high-quality wireless digital speech communications." IEEE Transactions on Vehicular Technology 43, no. 4 (1994): 934–45. http://dx.doi.org/10.1109/25.330156.

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30

Shim, Yongwoon, and Dong-Hee Shin. "Analyzing the development of 4th generation mobile network in China: actor network theory perspective." info 17, no. 1 (January 12, 2015): 22–38. http://dx.doi.org/10.1108/info-09-2014-0041.

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Purpose – This paper aims to provide an in-depth analysis of the process of standards setting based on the case of long-term evolution time division duplex (LTE TDD) deployment in China. Design/methodology/approach – Using actor-network theory (ANT) as a theoretical framework, multi-level analyses are presented to explain the process of adoption of LTE TDD at a global level. Findings – Findings identified the complex interaction between the social and technical aspects of fourth-generation (4G) by highlighting the co-evolving nature, diversity and interface that constitute the next-generation network environment. Research limitations/implications – ANT provides a framework of ideas for describing the process of technology adoption and for developing stories that explain it. Originality/value – The findings shed light on a critical insight of the interrelationships between TD-SCDMA and LTE TDD and identify the policy successes and failures of 4G mobile networks.

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31

Zhang, X., H. H. Chen, Z. Ding, K. K. Leung, M. Peng, and W. Wang. "Performance of network-coding-assisted scheduling schemes and their applications in uplink time division duplexing code division multiple access systems." IET Communications 5, no. 17 (November 25, 2011): 2558–68. http://dx.doi.org/10.1049/iet-com.2010.1045.

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32

K.Venkatesh, G., and P. V.Rao. "Performance analysis of a novel method for fast handovers in TDD and FDD for long term evolution." International Journal of Engineering & Technology 7, no. 1.9 (March 1, 2018): 115. http://dx.doi.org/10.14419/ijet.v7i1.9.9745.

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The LTE Long Term Evolution highly developed Technology, Handover is the essential function of the mobility of user in cellular networks in Time Division Duplex as well as Frequency Division Duplex. Handover is one of the essential that can affect the [QoS] Quality of Service with Capacity of Mobile Broadband Networks. Within mobile cellular network communication systems, a (spectrum) limited shared resource needs to be shared with all the users, so full duplex communication is achieved. This paper involves studying diverse Hand over delay parameters and also focus on reducing “Hard Handover delay” by minimizing interruption time, activation time, wireless channel accesses time as well as the wireless link transmission delay. Technique is developed in order to reduce the handover delay time in Time Division Duplex network which too reduces the wireless channel access time and the wireless link transmission delay. A novel handover algorithm is developed which would decreases the handover delay time and access time inside mobile network environment.Additional work may be conceded on to obtain enhanced performance and Quality of service in Time Division Duplex mobile network.

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33

Sulaeman, Enceng, Yaya Sulaeman, and Asep Yudi Hercuadi. "Desain dan Implementasi Duplekser dengan Metoda Pseudo-Interdigital untuk Uplink dan Downlink LTE." Jurnal Elektronika dan Telekomunikasi 13, no. 2 (June 29, 2016): 73. http://dx.doi.org/10.14203/jet.v13.73-80.

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Duplekser merupakan perangkat yang dapat mengisolasi receiver dari transmitter saat keduanya saling berbagi antena yang sama, digunakan agar komunikasi bisa berjalan secara full duplex. Ada dua metode transmisi duplex yaitu frequency division duplex (FDD) dan time division duplex (TDD). FDD merupakan teknik duplex yang menggunakan dua frekuensi yang berbeda untuk melakukan komunikasi dalam dua arah, sedangkan TDD menggunakan frekuensi tunggal dan frekuensi tersebut digunakan oleh semua kanal untuk melakukan pengiriman dan penerimaan data. Gabungan dua bandpass filter dengan metoda pseudo-interdigital untuk aplikasi LTE (long term evolution). Metode ini lebih unggul dibandingkan duplekser dengan metoda hybrid. Duplekser bekerja pada FDD LTE band ke-7 yaitu frekuensi uplink 2500-2570 MHz dan downlink 2620-2690 MHz. Dari hasil pengukuran diperoleh sebagai berikut: nilai frekuensi center pada uplink 2639 MHz dan pada downlink 2659 MHz, insertion loss pada uplink 1,561 dB dan downlink 1,74 dB, bandwidth ±70 MHz, isolasi 23,03 dB, serta nilai return loss 23,5 dB pada uplink dan downlink 23,45 dB.

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34

Papadopoulos, H. C., and C. E. W. Sundberg. "Shared time-division duplexing (STDD): impact of runlengths of dropped packets and fast-speech activity detection." IEEE Transactions on Vehicular Technology 47, no. 3 (1998): 856–70. http://dx.doi.org/10.1109/25.704840.

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Faregh, Effatsadat, and Mohammad Javad Dehghani. "Performance analysis of MIMO and MISO time division duplexing wireless links with SWIPT and antenna selection." Wireless Networks 26, no. 6 (May 12, 2020): 4517–28. http://dx.doi.org/10.1007/s11276-020-02337-9.

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Kalidoss, R., M. A. Bhagyaveni, and K. S. Vishvaksenan. "A Location-Based Duplex Scheme for Cost Effective Rural Broadband Connectivity Using IEEE 802.22 Cognitive Radio Based Wireless Regional Area Networks." Fluctuation and Noise Letters 13, no. 04 (October 20, 2014): 1450028. http://dx.doi.org/10.1142/s021947751450028x.

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The search for a method of utilizing the scarce spectrum in an efficient manner is an active area of research in both academic and industrial communities. IEEE 802.22 is a standard for wireless regional area network (WRAN) based on cognitive radio (CR) that operates over underutilized portions of TV bands (54–862 MHz). Time division duplex (TDD)-based WRAN cells have such advantages as dynamic traffic allocation, traffic asymmetry to users and ease of spectrum allocation. However, these cells suffer from severe cross time slot (CTS) interference when the frames of the cells are not synchronized with adjacent WRAN cells. In this paper, we evaluate the location-based duplex (LBD) scheme for eliminating the CTS interference. The proposed LBD system is much more flexible and efficient in providing asymmetric data service and eliminating CTS interference by exploiting the advantages of both TDD and frequency division duplex (FDD) schemes. We also compare the performance of LBD systems with virtual cell concepts. Furthermore, our simulation results reveal that LBD-based systems outperform the virtual cell approach in terms of the low signal-to-interference (SIR) ratio requirement by mitigating the effects of CTS.

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HOSSAIN, EKRAM, and VIJAY K. BHARGAVA. "LINK-STATE AWARE DYNAMIC TRAFFIC SCHEDULING FOR PROVIDING PREDICTIVE QoS IN WIRELESS MOBILE MULTIMEDIA NETWORKS." Journal of Interconnection Networks 01, no. 03 (September 2000): 221–45. http://dx.doi.org/10.1142/s0219265900000147.

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The performance of a centralized traffic priority based dynamic burst-level cell scheduling scheme is investigated in a correlated fading channel. The scheduling scheme is designed for the transmission of multiservice traffic over TDMA (Time Division Multiple Access)/TDD (Time Division Duplex) channels in a WATM (Wireless ATM) network. In this scheme, the number of slots allocated to a VC (Virtual Circuit) during a frame-time is changed dynamically depending on the traffic type, system traffic load, TOE (Time of Expiry) value of the data burst and data burst length. While allocating bandwidth, the channel error status is also taken into consideration. SR-ARQ (Selective Repeat - Automatic Repeat Request)-based link-level error control is assumed for all the traffic types in a multiservice traffic environment. The performance of the proposed scheme under correlated Rayleigh fading is evaluated using computer simulation for realistic voice, video and data traffic models and the QoS (Quality of Service) requirements of different traffic classes in a wireless mobile network. Simulation results show that the proposed scheduling framework can provide reasonably high channel utilization with predictive QoS guarantee in a multiservice traffic environment. The channel utilization and the perceived QoS for different services is highly affected by the traffic burstiness of the corresponding traffic type. Such a scheme can result in an energy efficient TDMA/TDD medium access control protocol for broadband wireless access.

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Xue, Linshan, Xue Li, Weiren Wu, and Yikang Yang. "Design of Tracking, Telemetry, Command (TT&C) and Data Transmission Integrated Signal in TDD Mode." Remote Sensing 12, no. 20 (October 13, 2020): 3340. http://dx.doi.org/10.3390/rs12203340.

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For satellite or aircraft networks, tracking, telemetry, and control (TT&C) and data transmission between different nodes are necessary. Traditional measurement mostly adopts the frequency division duplex (FDD) mode and uses a continuous measurement system to achieve high-precision measurement. However, as the number of network nodes increases, the mode suffers from complex frequency domain allocation, and high-cost measurement and data transmission equipment is required. This paper proposes the integrated signal in time division duplex (TDD) mode to improve frequency utilization to address these circumstances. The proposed signal can transmit the TT&C and data at the same frequency. In addition, the high-precision time-frequency synchronization and relative measurement technology in the TDD mode for distributed spacecraft or aircraft networks are studied. The simulation results show that the signal can work normally when the Doppler extrapolation error is less than a quarter of the integration frequency. The distance extrapolation error should be less than a quarter of the length of a chip. The integrated signal reduces the frequency band occupation and realizes the integration of TT&C and data transmission. In addition, the measurement performance is reduced by only 2~3 dB compared with that of the traditional pure TT&C signal.

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Liu, Zu-Jun, De-Chun Sun, Ke-Chu Yi, and Jie-Ling Wang. "Impact and compensation of I/Q imbalance on channel reciprocity of time-division-duplexing multiple-input multiple-output systems." IET Communications 7, no. 7 (May 1, 2013): 663–72. http://dx.doi.org/10.1049/iet-com.2012.0620.

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Hakim, N. F. A., T. Hariyadi, A. B. Pantjawati, and B. Mulyanti. "Analysis high gain waveguide slot antenna 2.3 GHz for Long Term Evolution-Time Division Duplex (LTE-TDD)." IOP Conference Series: Materials Science and Engineering 850 (May 23, 2020): 012054. http://dx.doi.org/10.1088/1757-899x/850/1/012054.

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41

Nilofer, Shaik. "A Review of Massive Multiple Input Multiple Output for 5G Communication: Benefits and Challenges." International Journal of Intelligent Communication, Computing and Networks 1, no. 1 (August 25, 2020): 22–26. http://dx.doi.org/10.51735/ijiccn/001/09.

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Massive MIMO (mMIMO) systems become a primary advantage to overcome the problem of bandwidth restrictions. It improves the channel capacity of remote systems.The paper reviews about mMIMO systems. mMIMO consists of several number of antennas at base station (BS) which improves spectrum efficacy. The extra benefit of the mMIMO system is that the components cost is low because of utilization of less power components. The paper also discusses about the channel estimation at the BS and generally time division mode (TDD) is assumed for mMIMO systems. The paper also discusses system model, benefits for 5G wireless communication and its challenges.

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Wang, Hung-Hsiang, Hsin-An Hou, and Jyh-Cheng Chen. "Design and Analysis of an Antenna Control Mechanism for Time Division Duplexing Distributed Antenna Systems Over High-Speed Rail Communications." IEEE Transactions on Emerging Topics in Computing 4, no. 4 (October 2016): 516–27. http://dx.doi.org/10.1109/tetc.2015.2414231.

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Jiang, Zheng, Bin Han, Peng Chen, Fengyi Yang, and Qi Bi. "Design of Joint Spatial and Power Domain Multiplexing Scheme for Massive MIMO Systems." International Journal of Antennas and Propagation 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/368463.

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Massive Multiple-Input Multiple-Output (MIMO) is one of the key techniques in 5th generation wireless systems (5G) due to its potential ability to improve spectral efficiency. Most of the existing works on massive MIMO only consider Time Division Duplex (TDD) operation that relies on channel reciprocity between uplink and downlink channels. For Frequency Division Duplex (FDD) systems, with continued efforts, some downlink multiuser MIMO scheme was recently proposed in order to enable “massive MIMO” gains and simplified system operations with limited number of radio frequency (RF) chains in FDD system. However these schemes, such as Joint Spatial Division and Multiplexing (JSDM) scheme and hybrid precoding scheme, only focus on multiuser transmission in spatial domain. Different from most of the existing works, this paper proposes Joint Spatial and Power Multiplexing (JSPM) scheme in FDD systems. It extends existing FDD schemes from spatial division and multiplexing to joint spatial and power domain to achieve more multiplexing gain. The user grouping and scheduling scheme of JSPM is studied and the asymptotic expression for the sum capacity is derived as well. Finally, simulations are conducted to illustrate the effectiveness of the proposed scheme.

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Zhang, Xiang, Xinyu Gu, Wenyu Li, Lin Zhang, Jia Shen, and Yi Wan. "The Study of Indoor and Field Trials on2×8MIMO Architecture in TD-LTE Network." International Journal of Antennas and Propagation 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/181579.

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With the development of mobile internet service, long-term evolution (LTE) system was proposed in the third generation partnership project (3GPP) to provide higher data rates and frequency efficiency. Since the year of 2010, 113 LTE networks have been commercially deployed worldwide, and most of the networks are based on frequency division duplexing (FDD). In this paper, measurement methods of four MIMO transmission modes (TMs) in time division-LTE (TD-LTE) are studied and analyzed. Link level simulation is carried out to evaluate the downlink throughput for different signal-to-noise ratios and parameter settings. Furthermore, indoor and field tests are also presented in the paper to investigate how real-world propagation affects the capacity and the error performance of MIMO transmission scheme. For the indoor test, radio channel emulators are applied to generate realistic wireless fading channel, while in the field trials, a live TD-LTE experiment cellular network is built, which contains several evolved nodeBs (eNBs) and a precommercial user equipment (UE). It is shown from both simulation and tests results that MIMO deployment gives a substantial performance improvement compared with the third generation wireless networks.

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Zhang, Weipeng. "Design of Radio Frequency Link in Automatic Test System for Multimode Mobile Communication Base Station." International Journal of Bifurcation and Chaos 25, no. 14 (December 30, 2015): 1540032. http://dx.doi.org/10.1142/s0218127415400325.

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A modularized design for the radio frequency (RF) link in automatic test system of multimode mobile communication base station is presented, considering also the characteristics of wireless communication indices and composition of signals of base stations. The test link is divided into general module, time division duplex (TDD) module, module of spurious noise filter, module of downlink intermodulation, module of uplink intermodulation and uplink block module. The composition of modules and link functions are defined, and the interfaces of the general module and the module of spurious noise filter are described. Finally, the estimated gain budget of the test link is presented. It is verified by experiments that the system is reliable and the test efficiency is improved.

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Winarti, Titin. "SISTEM KOMUNIKASI SELULER DENGAN UNIVERSAL MOBILE TELEPHONE SYSTEM ( UMTS )." Jurnal Transformatika 4, no. 2 (January 30, 2007): 50. http://dx.doi.org/10.26623/transformatika.v4i2.19.

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<span>Sistem celuler GSM memiliki beberapa kekurangan, yaitu tidak mampu untuk mengintegrasikan layanan video call dan video streaming karena kecepatan data masih rendah. Dengan alasan itu, maka ETSI menentukan migrasi dari GSM ke sistem generasi seluler ketiga yang disebut dengan UMTS (Universal Mobile Telephone System). Adapun spektrum frekuensi UMTS terestrial bekerja pada 1920-1980 MHz, 2110-2170 MHz untuk dipasangkan dari band dan 1900-1920 MHz, 2010-2025 MHz untuk tidak berpasangan dari band Seiring dengan perkembangan teknologi, teknologi telekomunikasi sistem seluler terus berkembang dan menggarap sekarang telah mencapai generasi ketiga yang dikenal dengan nama dari International Mobile Telecommunications-2000 (IMT-2000). Adapun kerangka kerja untuk pengembangan teknologi seluler generasi ketiga (3G) di Eropa adalah Universal Mobile Telephone System (UMTS). UMTS menggunakan disebut oleh TD-CDMA multiple access adalah UTRA TDD (UMTS Terrestrial Radio Access dari Time Division Duplex) dan W-CDMA untuk UTRA FDD DARI (UMTS Terrestrial Radio Access dari Duplex Frekuensi Division Kata kunci : UMTS, multiple access, Sistem Seluler</span>

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Kusuma, Fadli, and Hasanah Putri. "Increasing LTE-Advanced Network Capacity Using The Inter-band Carrier Aggregation (Downlink Side) Method." JURNAL INFOTEL 12, no. 2 (May 29, 2020): 52–59. http://dx.doi.org/10.20895/infotel.v12i2.474.

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According to the identification of the Operating Support System (OSS) by the Smartfren cellular operator in the Central Bandung area, six sites are found to have high traffic capacity with the physical resource block (PRb) percentage of 82.6 %. The use of PRb > 80 % is included in the warning indicator 2 based on the operator’s standards. It is also strengthened by the condition of the existing sites with the average Reference Signal Receive Power (RSRP) of -103.3 dBm, Signal to Interference Noise Ratio (SINR) of 6.28 dB, and throughput of 27.78 Mbps, thus resulting in non-optimal network performance in the area. Therefore, in this study, the inter-band Carrier Aggregation (CA) was applied by combining the 40 Time Division Duplex (TDD) band (2300 MHz) and band 5 Frequency Division Duplex (FDD) (850 MHz). One of the advantages of applying this method is that it can increase the user network capacity by maximizing the resources owned by the operator. The predetermined scenario taking into account the initial network condition indicated a decrease in the PRb percentage by 44.50 % and an increase in the average RSRP value by 12.8 dBm, SINR by 5.14 dB, and throughput by 34.59 Mbps.

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Yaqoob, Y. J. I. A., W. L. Pang, S. K. Wong, and K. Y. Chan. "Performance evaluation of video streaming on LTE with coexistence of Wi-Fi signal." Bulletin of Electrical Engineering and Informatics 8, no. 3 (September 1, 2019): 890–97. http://dx.doi.org/10.11591/eei.v8i3.1580.

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The continuous growth in mobile data traffic and limited license wireless spectrum have led to dramatically increase the demand of the radio spectrum. It is widespread the concern about the coexistence of long term evolution (LTE) and Wi-Fi in the unlicensed band. There are several techniques have been proposed to enable the coexistence of LTE and Wi-Fi in the unlicensed band, but these works are targeted on the impact of the LTE to the Wi-Fi network performance. An experiment is carried out in this work to evaluate the impact of Wi-Fi signal on the video streaming in the LTE network. The experimental test comprised of the national instrument (NI) universal software radio peripheral (USRP) 2953R that is controlled by the LabVIEW Communication LTE application framework. Extensiveexperiments are carried out under two scenarios, i.e. (1) Coexistence of LTE and Wi-Fi signal, (2) LTE signal only. Performance evaluations are carried out with different Modulation and coding schemes (MCS) values and different mode of operations, i.e. frequency division duplex (FDD) and time division duplex (TDD) mode. The results illustrated that the interference from Wi-Fi signal caused the performance degradation of the LTE network in throughput and the power received by user equipment (UE).

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Zhong, Shida, Haogang Feng, Peichang Zhang, Jiajun Xu, Huancong Luo, Jihong Zhang, Tao Yuan, and Lei Huang. "Deep Learning Based Antenna Selection for MIMO SDR System." Sensors 20, no. 23 (December 7, 2020): 6987. http://dx.doi.org/10.3390/s20236987.

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In this paper, we propose and implement a novel framework of deep learning based antenna selection (DLBAS)-aided multiple-input–multiple-output (MIMO) software defined radio (SDR) system. The system is constructed with the following three steps: (1) a MIMO SDR communication platform is first constructed, which is capable of achieving uplink communication from users to the base station via time division duplex (TDD); (2) we use the deep neural network (DNN) from our previous work to construct a deep learning decision server to assist the MIMO SDR platform for making intelligent decision for antenna selection, which transforms the optimization-driven decision making method into a data-driven decision making method; and (3) we set up the deep learning decision server as a multithreading server to improve the resource utilization ratio. To evaluate the performance of the DLBAS-aided MIMO SDR system, a norm-based antenna selection (NBAS) scheme is selected for comparison. The results show that the proposed DLBAS scheme performed equally to the NBAS scheme in real-time and out-performed the MIMO system without AS with up to 53% improvement on average channel capacity gain.

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Kim, Kyunghoon, Hyunwook Yang, Jaehyun Jang, Tiefeng Sun, Seungwon Choi, and Jaeho Jung. "Online Calibration for LTE-Based Antenna Array System." International Journal of Antennas and Propagation 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/2645870.

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This paper presents a novel calibration method that equalizes the impulse responses of all the Radio Frequency (RF) modules of an antenna array system operating in Long-Term Evolution (LTE) evolved NodeB (eNB). The proposed technique utilizes the Zadoff-Chu (Z-C) sequence of the Primary Synchronization Signal (PSS) and Sounding Reference Signal (SRS) that are available in every LTE data frame for downlink and uplink, respectively, for estimating and compensating the differences in the impulse responses among the RF modules. The proposed calibration method is suitable for wide bandwidth signal environments of LTE because it equalizes the impulse response of each RF module, which is ultimately equivalent to compensate the phase and amplitude differences among RF modules for the entire frequency band. In addition, the proposed method is applicable while the target eNB is transmitting or receiving a data stream. From various experimental tests obtained from a test-bed implemented with 2 RF modules, it has been verified that the proposed method provides a reliable calibration for Release 10 Time Division Duplex (TDD) LTE signals. Phase errors after the calibration in our test-bed have been found to be about 2.418° and 2.983° for downlink and uplink, respectively.

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